When I last time played 
As a Terran I must fit into very small timing windows and thus having buildings spending as little time in transit between add-ons as possible is very important.
And so is the position of the Reactor of the first Barrack. Having Reactor in the wall is a BIG disadvantage if your opponent is playing something fishy, so if you spawned on the wrong side of the map you already start with disadvantage. In some maps however you can put Barracks in a way that Reactor would still be built not inside the wall.
As a Protoss not having proper wall in the natural is often an auto-GG vs Zerg, and not having a Reaper wall in main is giving a significant advantage for free vs Terran.
I do not however think about such things when I play because I have played thousands of games already, and because for each new map I take my time to launch it alone in custom to check where I need to put my buildings to have the most optimal wall positioning.
Well, WarCraft did not had much strategy to be honest: builds were rudimental, unit compositions were usually not affected by opponents choices and you choice of Hero(es) did not matter much: today people often play in a mod where you get random Heroes…
As for HoMM3 90% of its multiplayer gameplay can be described as “solving chess puzzles in a minimal time possible”. Or even “remembering solutions to these puzzles”. This can be pretty fun activity, but does this still count as strategy?
Oh, these guys do a lot of strategic choices when they play.
If you want to know what specifically I suggest you watch series “I Played In A $2500 Tournament, Here’s How It Went” by uThermal, where Mark playes on a real tournament and comments his every action and explain choices that he makes.
Or “HarsteamCasts” channel where - unlike most casters - Kevin most of the time talks a lot about choices made by players, why it mattered, and why the were wrong/good choices.
And speaking of Harstem, in his “IIIODIS” series he makes fun of people doing various mistakes but most of all he focuses attention on wrong choices made. For Diamond and above it is usually wrong choices done by players that caused them to loose, not mistakes in micro or macro.
For us mere mortals what matters in this game a lot is having a good build - which IS a strategy - and having a good plan for the game - which IS a strategy - and be able to adjust this plan according to what happens in the game - which also IS a strategy.
And speaking of builds, one thing that progamers do and we don’t is the mindgame: all games we play on the ladder are BO1 while progamers play at least BO3.
This is one of the biggest failures of SC2 game design…